Planar magnetic head

ABSTRACT

A magnetic head including a second magnetic pole (P2 pole) that is fabricated upon a write gap layer that is deposited upon a flat surface. To achieve the flat surface, a P1 pole pedestal is formed upon the P1 pole layer with a sufficient thickness that the induction coil structure can be fabricated beneath the write gap layer. In the preferred embodiment, an etch stop layer is formed upon the P1 pole layer and an ion etching process is utilized to form the induction coil trenches in an etchable material that is deposited upon the etch stop layer. Following the fabrication of the induction coil structure a CMP process is conducted to obtain a polished flat surface upon which to deposit the write gap layer, and the P2 pole is then fabricated upon the flat write gap layer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to magnetic heads for hard diskdrives, and more particularly to magnetic heads having planar P2 polesand methods for fabricating such heads.

2. Description of the Prior Art

A well known method for increasing the areal data storage density onmagnetic hard disks is to fabricate the magnetic data recording headwith a narrower P2 pole tip, such that a narrower data track is writtenby the head. However, in typical magnetic heads, the fabrication of theinduction coils of the head results in an uneven topology upon which theP2 pole is fabricated. As a result of the uneven topology, thefabrication of the P2 pole tip is affected, in that it is more difficultto reliably create the narrow pole tip dimensions that are desired. Thusfabrication of narrower P2 pole tips will be made easier where the P2pole, including the P2 pole tip and the yoke portions of the P2 pole,are fabricated on a planar surface. As is described herebelow, thepresent invention includes fabrication steps that provide a planarizedsurface upon which the P2 pole and P2 pole tip are fabricated.

SUMMARY OF THE INVENTION

The magnetic head of the present invention, includes a second magneticpole (P2 pole) that is fabricated upon a write gap layer that isdeposited upon a flat surface. To achieve the flat surface, a P1 polepedestal is formed upon the P1 pole layer with a sufficient thicknessthat the induction coil structure can be fabricated beneath the writegap layer. In the preferred embodiment, an etch stop layer is formedupon the P1 pole layer and an ion etching process is utilized to formthe induction coil trenches in an etchable material that is depositedupon the etch stop layer. Following the fabrication of the inductioncoil structure a CMP process is conducted to obtain a polished flatsurface upon which to deposit the write gap layer, and the P2 pole isthen fabricated upon the flat write gap layer.

The magnetic head of the present invention can be reliably fabricatedwith a more narrow P2 pole tip base width, such that data tracks writtenby the magnetic head are likewise narrower. A hard disk drive includingthe magnetic head of the present invention therefore possesses narrowerwritten data tracks, such that the areal data storage density of thehard disk drive is increased.

It is an advantage of the hard disk drive of the present invention thatit possesses increased areal data storage density.

It is another advantage of the hard disk drive of the present inventionthat data is written with narrower data track widths upon the disk mediaof the hard disk drive.

It is an advantage of the magnetic head of the present invention that itincludes a P2 pole that is fabricated upon a flat surface.

It is another advantage of the magnetic head of the present inventionthat it is fabricated with a flat write gap layer, whereby the P2 pole,and including the P2 pole tip is fabricated upon a flat surface.

It is a further advantage of the magnetic head of the present inventionthat it is fabricated with an induction coil structure that is disposedbeneath the write gap layer, whereby the write gap layer is fabricatedupon a flat surface and the P2 pole is fabricated upon the flat writegap layer.

It is an advantage of the method for fabricating a magnetic head of thepresent invention that a flat surface is provided for the fabrication ofthe P2 pole thereon.

It is another advantage of the method for fabricating a magnetic head ofthe present invention that the induction coil structure is fabricatedbeneath the write gap layer, and a flat write gap layer is fabricatedthereon, such that the P2 pole can be fabricated on the write gap layer.

It is a further advantage of the method for manufacturing a magnetichead of the present invention that a P1 pole pedestal is fabricated upona P1 pole, such that the induction coil structure can be fabricatedbeneath the write gap layer, and a flat write gap layer can befabricated thereon, and a flat P2 pole can be fabricated on the writegap layer.

These and other features and advantages of the present invention will nodoubt become apparent to those skilled in the art upon reading thefollowing detailed description which makes reference to the severalfigures of the drawings.

IN THE DRAWINGS

FIG. 1 is a simplified depiction of a hard disk drive of the presentinvention;

FIG. 2 is a side cross-sectional view of a fabrication step of themagnetic head of the present invention which serves as a starting pointfor the detailed description thereof;

FIG. 3 is a side cross-sectional view depicting the fabrication of theP1 pedestal of the present invention;

FIG. 4 is an end cross-sectional view of the device depicted in FIG. 3,taken along lines 4—4 of FIG. 3;

FIGS. 5–11 are side cross-sectional views depicting further fabricationsteps of the present invention; and

FIGS. 12 and 13 are end cross-sectional views of further fabricationsteps of the present invention, wherein FIG. 12 is taken along lines12—12 of FIG. 11;

FIG. 14 is a side cross-sectional view of a further fabrication step ofthe present invention; and

FIGS. 15 and 16 are end cross-sectional views depicting furtherfabrication steps of the present invention, wherein FIG. 15 is takenalong lines 15—15 of FIG. 14.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a top plan view that depicts significant components of a harddisk drive which includes the magnetic head of the present invention.The hard disk drive 10 includes a magnetic media hard disk 12 that isrotatably mounted upon a motorized spindle 14. An actuator arm 16 ispivotally mounted within the hard disk drive 10 with a magnetic head 20of the present invention disposed upon a distal end 22 of the actuatorarm 16. A typical hard disk drive 10 may include a plurality of disks 12that are rotatably mounted upon the spindle 14 and a plurality ofactuator arms 16 having a magnetic head 20 mounted upon the distal end22 of the actuator arms. As is well known to those skilled in the art,when the hard disk drive 10 is operated, the hard disks 12 rotate uponthe spindle 14 and the magnetic heads 20 are contained in air bearingsliders that are adapted for flying above the surface of the rotatingdisks. Such sliders include a substrate base upon which the variouslayers and structures that form the magnetic head are fabricated. Suchheads are fabricated in large quantities upon a wafer substrate andsubsequently sliced into discrete magnetic heads 20.

FIG. 2 is a side cross-sectional view of the magnetic head 20 at anappropriate fabrication stage to commence the discussion of the presentinvention. This fabrication stage is well known to those skilled in theart, and it includes a read head magnetic shield (S1) layer 24 that isfabricated upon the upper surface 26 of a wafer substrate 27; a readhead element 28 that is fabricated within insulative layers 32 upon theS1 shield 24, and a second magnetic shield (S2) layer 36 that isfabricated upon the insulative layers 32. A further insulative layer 40is deposited upon the S2 shield 36 and a first magnetic pole (P1) 50 isnext fabricated upon the insulative layer 40. As is also well known tothose skilled in the art, in a type of magnetic head termed a mergedhead, the P1 pole layer 50 and the S2 shield layer 36 are merged into asingle layer that performs the functions of the S2 shield 36 when thehead is reading data from a hard disk, and performs the function of theP1 magnetic pole layer when the magnetic head is writing data to a harddisk. The insulative layer 40 is not present in such a merged head. Thepresent invention, as is next discussed in detail, may be fabricated asa standard magnetic head or as a merged magnetic head, as will be clearto those skilled in the art upon reading further.

The next step in the fabrication of the magnetic head 20 of the presentinvention is the creation of a stepped P1 pole as is depicted in FIGS. 3and 4, wherein FIG. 3 is a side cross-sectional view and FIG. 4 is anend elevational view taken along lines 4—4 of FIG. 3. The stepped P1pole is created by fabricating an additional raised P1 pole segment orpedestal 60 in magnetic connection with the P1 pole layer 50 proximatethe ABS surface 62 of the magnetic head 20. Additionally, a P1 pole backgap piece 64 is also fabricated in magnetic connection with the P1 polelayer 50. The P1 pole pedestal 60 and back gap piece 64 may befabricated utilizing a patterned photoresist and well knownphotolithographic techniques to plate the pedestal 60 and back gap piece64 onto the P1 layer 50. Where the photolithographic techniques areutilized, the pedestal 60 and back gap piece 64 may be fabricated fromthe same material as the P1 layer, such as Permalloy, or they may befabricated from another magnetically conductive material, such as NiFe45/55 which has different magnetic conductive properties from Permalloy,and thus provides different performance characteristics to a magnetichead that is fabricated using it. Alternatively, the P1 pedestal 60 andback gap piece 64 can be created by first fabricating a thick P1 layerand then selectively etching away portions of the P1 layer while maskingthe pedestal 60 and back gap piece 64, until suitable pedestal thicknessis obtained. As is more fully described herebelow, the thickness of thepedestal 60 is generally at least equal to the thickness of inductioncoil members that are subsequently fabricated within the magnetic head20, as are described herebelow. As depicted in FIG. 4, the pedestal 60is generally fabricated centrally above the read head element 28, andthe width of the pedestal 60 is not a critical dimension if fabricatedgenerally in the proportions shown in the drawings. Following thefabrication of the P1 pedestal 60, an insulation layer 66 is depositedupon the surface of the device. As will become clear upon furtherreading, the insulation layer 66 acts as an etch stop layer in asubsequent fabrication step; therefore, the composition of theinsulation layer 66 is determined in part by the composition of othermaterial layers that are described herein.

As depicted in FIG. 5, a further layer 70 of dielectric or insulativematerial is deposited on top of the etch stop layer 66. The thickness ofthe layer 70 is greater than the thickness of the P1 pedestal 60 in thata chemical mechanical polishing (CMP) step, as depicted in FIG. 6 isnext performed. The purpose of the CMP step is to create a flat surface74 upon the wafer substrate, including the dielectric layer 70, P1pedestal 60 and back gap piece 64 as shown in FIG. 6. Thereafter, asdepicted in FIG. 7, a patterned etch mask 80 is fabricated upon the Natsurface 74. The patterned mask includes openings 84 for fabricatinginduction coil trenches as are next described.

As depicted in FIG. 8, utilizing an ion etch process which is preferablya reactive ion etch (RIE) process, induction coil trenches 90 are etchedthrough the dielectric layer 70 to the etch stop layer 66. Therefore,the relationship of the materials which comprise the etch stop layer 66and the dielectric layer 70 must be such that during the RIE step thematerial comprising layer 70 is etched, while the material comprisingthe etch stop layer 66 is not etched. By way of example, where the layer70 is composed of an organic polymer such as a hard baked resist, areactive ion etch process utilizing a gas such as oxygen can be utilizedand the etch stop layer 66 may consist of a substance that issubstantially more difficult to etch, such as SiO₂ or Al₂O₃.Accordingly, where the dielectric layer 70 is composed of SiO₂, the etchstop layer 66 is preferably composed of Al₂O₃ and a gas such as fluorineis utilized in the RIE process.

Thereafter, as depicted in FIG. 9, a seed layer 92 is next depositedonto the substrate and into the coil trenches 90. As is known in theart, a typical seed layer 92 is preferably a sputter deposited duallayer composed of a tantalum initial sublayer part and a coppersubsequent sublayer part.

An induction coil structure is then fabricated by depositing inductioncoil material 94 into the coil trenches 90. It is significant to notethat the etch stop layer 66 is electrically insulative to prevent theshorting out of the induction coil traces. The induction coil istypically composed of copper, and is fabricated in a standardelectrodeposition process that is well known to those skilled in theart. Thereafter, as depicted in FIG. 10, a second CMP process step isconducted to remove the excess copper and the RIE mask 80, such that aflat upper surface 100 is formed. It is significant to note that theupper surface 104 of the back gap piece 64 is exposed in this CMPprocess. The seed layer 92 and induction coil traces 106 remain in thetrenches 90.

As depicted in FIGS. 11 and 12, a patterned write gap layer 110 is nextdeposited upon the flat surface 100, such that the write gap layer 110is formed with a flat upper surface 112. FIG. 11 is a sidecross-sectional view similar to FIGS. 2, 3 and 5–10, and FIG. 12 is anend cross-sectional view taken along lines 12—12 of FIG. 11 and similarto FIG. 4. The patterning of the write gap layer 110 provides an opening114 to expose the upper surface 104 of the back gap piece 64, an opening118 to expose the upper surface 120 of a central induction coil tracepad 122 for a subsequent electrical connection thereto, as is well knownto those skilled in the art, and openings 124 on each side of the P2pole tip location (described below) to expose the upper surface 126 ofthe insulative layer 70 at the ABS surface 62. Thereafter, as depictedin the end cross-sectional view of FIG. 13, a patterned photoresist 128is fabricated upon the flat upper surface 112 of the write gap layer 110as a part of standard photolithographic steps for the plating up of theP2 pole, including the P2 pole tip. The patterned photoresist 128 thusincludes a P2 pole tip trench 129. Portions of the patterned photoresist128 are formed upon the upper surface 126 of the insulative layer 70, asseen in FIG. 13.

The fabricated P2 pole 130 is depicted in FIGS. 14 and 15, wherein FIG.14 is a side cross-sectional view similar to FIG. 12, and FIG. 15 is anend cross-sectional view similar to FIG. 13. As depicted in FIGS. 14 and15, the P2 pole 130 including a P2 pole tip portion 134 is fabricatedonto the trench 129 upon the flat write gap layer 110. As is best seenin FIG. 15, the P2 pole tip 134 is generally centrally disposed relativeto the P1 pedestal 60 and in alignment with the read head element 28. Asdepicted in FIG. 16, following the fabrication of the P2 pole 130, thepatterned photoresist 128 is removed, typically by a wet chemicalprocess. Significantly, the insulative layer 70 at the ABS surface 62 isalso removed in the wet chemical photoresist removal process.Thereafter, as depicted in FIG. 16, the head is encapsulated in asuitable dielectric 138 such as alumina, and further standardfabrication steps (not shown) are conducted to produce a completedmagnetic head 20. In this embodiment only one dielectric material, thealumina 138, is exposed at the ABS surface 62, such that a subsequentABS lapping process can be optimized more easily, as will be understoodby those skilled in the art.

As was indicated hereabove, the width W of the base of the P2 pole tip(P2W) 134 is a significant operational parameter for magnetic heads, andthe narrower that P2W can be fabricated, the greater the areal datastorage density on a disk medium can be made. The photolithographicfabrication techniques described herein that are utilized to fabricatethe P2 pole tip can more reliably obtain narrow P2W widths in amanufacturing environment because the P2 pole, including the P2 poletip, is fabricated upon a flat write gap layer surface. The utilizationof the stepped P1 pole pedestal of the present invention allows theinduction coil traces to be fabricated beneath the write gap layer, suchthat the write gap layer can be deposited on a flat surface and the P2pole, and particularly the P2 pole tip, are then fabricated upon theflat write gap layer. The magnetic head 20 of the present invention isthereby more reliably fabricated with a narrow P2W width. As a result,the data track written by the head 20 is narrower and therefore theareal data storage density of the magnetic medium is increased. A harddisk drive that includes the magnetic head 20 of the present inventiontherefore has a greater data storage capacity.

While the invention has been shown and described with regard to certainpreferred embodiments, it is to be understood that those skilled in theart will no doubt devise certain alterations and modifications in formand detail hereof that nevertheless include the true spirit and scope ofthe invention. It is therefore intended that the following claims coverall such alterations and modifications hereof which nevertheless includethe true spirit and scope of the invention.

1. A magnetic head, comprising: a substrate; read head elements beingfabricated upon said substrate; a P1 pole being fabricated upon saidread head elements; a P1 pole pedestal being disposed upon said P1 polein magnetic connection therewith; an etch stop layer being disposed uponsaid P1 pole; an induction coil structure being fabricated upon saidetch stop layer; a flat upper surface being formed upon said P1 pedestaland said induction coil structure; a write gap layer being disposed uponsaid flat upper surface; and a P2 pole, including a body portion and aP2 pole tip portion, being disposed upon said write gap layer.
 2. Amagnetic head as described in claim 1 wherein said write gap layer issubstantially flat.
 3. A magnetic head as described in claim 2 whereinsaid P1 pedestal is approximately the same thickness as a thickness ofsaid induction coil structure.
 4. A magnetic head as described in claim2 wherein a back gap piece is disposed upon said P1 pole in magneticconnection therewith.
 5. A hard disk drive comprising: a motor forrotating a spindle; a magnetic medium disk mounted on said spindle; anactuator assembly including a magnetic head for writing magneticinformation on said disk, said magnetic head including: a substrate;read head elements being fabricated upon said substrate; a P1 pole beingfabricated upon said read head elements; a P1 pole pedestal beingdisposed upon said P1 pole in magnetic connection therewith; an etchstop layer being disposed upon said P1 pole; an induction coil structurebeing fabricated upon said etch stop layer; a flat upper surface beingformed upon said P1 pedestal and said induction coil structure; a writegap layer being disposed upon said flat upper surface; and a P2 pole,including a body portion and a P2 pole tip portion, being disposed uponsaid write gap layer.
 6. A hard disk drive as described in claim 5wherein said write gap layer is substantially flat.
 7. A hard disk driveas described in claim 6 wherein said P1 pedestal is approximately thesame thickness as a thickness of said induction coil structure.
 8. Ahard disk drive as described in claim 6 wherein a back gap piece isdisposed upon said P1 pole in magnetic connection therewith.